Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Pope Benedict Meets with British Leaders, Celebrates Mass VOA News 18 September 2010 Pope Benedict XVI conducts a mass in Westminster Cathedral in London, 18 Sep 2010 Photo: AP Pope Benedict XVI conducts a mass in Westminster Cathedral in London, 18 Sep 2010 Pope Benedict celebrated Mass at Westminster Cathedral Saturday on the third day of his historic four-day visit to Britain. Before the service, he met with Prime Minister David Cameron, his deputy Nick Clegg and acting Labor leader Harriet Harman. The Roman Catholic pontiff plans to wrap up Saturday with a prayer vigil in Hyde Park.  Opponents of the first papal state visit to Britain are marching through central London and holding a rally Saturday. On Friday, Pope Benedict became the first Roman Catholic leader to visit the London residence of the Archbishop of Canterbury since the Church of England broke with Rome in 1534. The pope and the archbishop, Rowan Williams, also conducted a joint prayer service at Westminster Abbey. Benedict pursued his full itinerary on Friday, after police announced the arrests of six men suspected of plotting an attack on the pope.  The suspects were officially identified only as street cleaners. British media have reported that some of them are of Algerian origin. A papal spokesman says the pontiff was informed of the arrests, but the Vatican does not consider the situation particularly dangerous. Turnout at some of the pope's public appearances has been less than expected, and he was greeted in London by some protesters. Many in Britain are angered by the Vatican's handling of priests who sexually abused children. Others disagree with the Vatican's stance on gay rights, abortion and contraception. Some information for this report was provided by AP. .